On Fri, 1 Apr 2016 12:33:18 +0200
Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:
> * Thomas Gleixner | 2016-03-14 09:49:52 [+0100]:
>
> >On Sun, 13 Mar 2016, Clark Williams wrote:
> >
> >> I'm hitting the WARN_ON(wakes > 2) in $SUBJECT when resuming from suspend on my laptop (quad-core i7 with HT on). Looks like the warning gets hit 36 times on resume. E.g.:
> >If resume is the only case, then we can filter that out and not worry about it
> >at all :)
>
> This works with the "mem" and "disk" target:
>
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -194,6 +194,12 @@ struct platform_freeze_ops {
> void (*end)(void);
> };
>
> +#if defined(CONFIG_SUSPEND) || defined(CONFIG_HIBERNATION)
> +extern bool pm_in_action;
> +#else
> +# define pm_in_action false
> +#endif
> +
> #ifdef CONFIG_SUSPEND
> /**
> * suspend_set_ops - set platform dependent suspend operations
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index bfd9e0982f15..fbb23f93e8d6 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -648,6 +648,10 @@ static void power_down(void)
> cpu_relax();
> }
>
> +#ifndef CONFIG_SUSPEND
> +bool pm_in_action;
> +#endif
> +
> /**
> * hibernate - Carry out system hibernation, including saving the image.
> */
> @@ -660,6 +664,8 @@ int hibernate(void)
> return -EPERM;
> }
>
> + pm_in_action = true;
> +
> lock_system_sleep();
> /* The snapshot device should not be opened while we're running */
> if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
> @@ -725,6 +731,7 @@ int hibernate(void)
> atomic_inc(&snapshot_device_available);
> Unlock:
> unlock_system_sleep();
> + pm_in_action = false;
> return error;
> }
>
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index 80ebc0726290..393bc342c586 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -522,6 +522,8 @@ static int enter_state(suspend_state_t state)
> return error;
> }
>
> +bool pm_in_action;
> +
> /**
> * pm_suspend - Externally visible function for suspending the system.
> * @state: System sleep state to enter.
> @@ -536,6 +538,8 @@ int pm_suspend(suspend_state_t state)
> if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
> return -EINVAL;
>
> + pm_in_action = true;
> +
> error = enter_state(state);
> if (error) {
> suspend_stats.fail++;
> @@ -543,6 +547,7 @@ int pm_suspend(suspend_state_t state)
> } else {
> suspend_stats.success++;
> }
> + pm_in_action = false;
> return error;
> }
> EXPORT_SYMBOL(pm_suspend);
> diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
> index 8459561f0379..205fe36868f9 100644
> --- a/kernel/sched/swait.c
> +++ b/kernel/sched/swait.c
> @@ -1,5 +1,6 @@
> #include <linux/sched.h>
> #include <linux/swait.h>
> +#include <linux/suspend.h>
>
> void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
> struct lock_class_key *key)
> @@ -42,7 +43,9 @@ void swake_up_all_locked(struct swait_queue_head *q)
> list_del_init(&curr->task_list);
> wakes++;
> }
> - WARN_ON(wakes > 2);
> + if (pm_in_action)
> + return;
> + WARN(wakes > 2, "complate_all() with %d waiters\n", wakes);
> }
> EXPORT_SYMBOL(swake_up_all_locked);
>
> Sebastian
Applied to 4.4.6-rt12, suspended/resumed multiple times with no warnings from swake_up_all_locked().
Tested-by: Clark Williams <williams@xxxxxxxxxx>
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